mysql - 如何在我的 sql 中添加总计作为最后一行？

Question

我正在尝试显示一行“总计”，它将对 Count 列进行总和。下面的代码将有两列，Environment 和 Count。

select 
case 
when env is null THEN 'Unknown' 
else env
end,
count(*) as Count
from env_table
group by env
order by env
/

我想要的输出：

视窗 200

Linux 120

总计 320

正如您在上面看到的，我想做的是在最后添加一个名为“Total”的行，它实际上会执行 SUM(count(*))。执行此操作的正确语法是什么？谢谢！

Answer 1

使用WITH ROLLUP修饰符GROUP BY：

SELECT   IFNULL(env, 'Unknown'),
         COUNT(*) AS Count
FROM     env_table
GROUP BY env WITH ROLLUP
ORDER BY env

Answer 2

也许是这样的？

SELECT   IFNULL(env, 'Unknown'),
         COUNT(*) AS Count
FROM env_table
GROUP BY env
ORDER BY env
UNION ALL
SELECT   null,
         Count(*)
FROM env_table

Answer 3

SELECT   COALESCE(env, 'Total') AS Description,
         COUNT(*) AS Count
FROM     env_table
GROUP BY env WITH ROLLUP
ORDER BY env

Answer 4

SELECT env, count 
  FROM (SELECT CASE WHEN env is null THEN 'Unknown' ELSE env END env,
               count(*) count
          FROM env_table
         GROUP BY env
      ORDER BY env)
UNION ALL
SELECT 'Total' env,
       count(*) count
  FROM env_table       

Answer 5

我希望它有效。以防万一，如果需要任何更正，很想听听我的错误。

select environment, count from table a
union all
(select "total" as environment, sum(count) from table b
group by 1)